1. Field of the Invention
The present invention relates to circuitry for providing optimum performance in high frequency dynamic servovalve controls.
2. Description of the Prior Art
Compensation circuitry for improving the peformance of servovalves has been advanced in the past. For example, U.S. Pat. No. 4,336,745 provides a servovalve linearization circuit for compensating for the basic orifice equation nonlinearity of the servovalve. The compensation circuit in U.S. Pat. No. 4,336,745 measures the pressure required by the load and then compensates the servovalve flow command signal based on the required pressure. This statically linearizes the servovalve device.
U.S. Pat. No. 4,537,077 adds a load dynamic compensation signal for specimen disturbances that are caused during displacement control into the servovalve command signal by utilizing the actuator pressure and acceleration and a derived compensating signal for the compliance factor of the oil in the actuator. The circuits of the two aforementioned patents preferably can be used in series, with the load dynamic compensation circuit of U.S. Pat. No. 4,537,077 added into the signal that is delivered to the compensation circuitry of U.S. Pat. No. 4,336,745.
A further servovalve limitation is caused by the lag of the servovalve spool response, which then becomes a significant factor in overall performance when the more apparent and larger effects have been compensated for with the circuitries just described.